iSpy
by CelebratoryPenguin
Summary: Sherlock spies on John and Sarah "in flagrante." In the name of research, you understand, purely scientific.


**iSpy**

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><p>It was a face that Sherlock had never seen before.<p>

Sherlock really had seen John's face before, of course, and had catalogued its varied expressions: exasperated, thrilled, pained, amused, concerned, sceptical. It was this new rendering that Sherlock wanted to commit to his vast memory.

_Cheeks flushed. Eyes wide. Lips parted, possibly to accommodate the rising respiratory rate._

Any one of John's non-Sherlock acquaintances would have averted his gaze, Sherlock thought as he made note of the way John's dimples deepened. He snorted softly at the idiocy of these lesser men.

_Pupils dilated, almost completely obscuring the blue of John's irises._

There were other areas of interest for Sherlock as John unbuttoned his shirt then shrugged out of it, letting it fall untidily to the floor.

_Surprisingly broad shoulders and narrow waist have been hidden beneath bulky civilian clothing, perhaps indicating that the military part of his life is something he also wants to hide away._

His view was obscured by something John's idiot friends probably would have enjoyed. A woman's silky hair was released from a clip and cascaded over her delicate, creamy shoulders. Sarah, stupid Sarah, blocking his view of John removing his jeans.

Stupid Sarah, drawing John's attention from more pressing matters.

Perhaps, Sherlock allowed himself to think, she was not entirely dim. She was a doctor, so she couldn't be a complete imbecile. Added to that, she had caught on to their line of work quickly, although she had incorrectly termed the crimes "puzzles." Certainly she had courage after the debacle with the Chinese smugglers; not many women would have let John come within fifty metres after being kidnapped and nearly murdered on the first date.

John was definitely within fifty metres. Not even fifty millimetres separated him from Sarah's nude, undulating body. Sherlock gave Sarah's pert breasts and slim thighs a cursory glance before returning to John's infinitely more interesting form.

_Skin flushing now extending downward to the neck and chest. Accelerated pulse visible at the carotid artery._

Sherlock theorized that while it was possible to suffer a stroke or heart attack during sexual activity, John's overall conditioning would probably prevent that in his case.

Good, because John's activity level was increasing. One hand at Sarah's waist, drawing her close. The other in her hair, at the back of her head, holding her in place while he kissed her. All Sherlock could see during the kisses was the back of Sarah's head and the tension in John's hand as he alternately tugged and caressed.

_Nails turning a bit white. Bloodflow is otherwise occupied._

Just how occupied the bloodflow had become was obvious a few seconds later when Sarah pushed John backward so that he collided with the bed, sitting down with a chuckle. When Sarah stood aside to step out of her panties, Sherlock could see John clearly and was quite impressed.

_Length and girth somewhat above average even though full arousal may not yet be achieved._

He made a mental note to compare in another few minutes, after Sarah dropped gracefully to her knees and lowered her head over John's erection. She had tossed her long hair over one shoulder, leaving Sherlock a clear view of turgid flesh disappearing into swollen, rosy lips.

_Slight upward curvature. Veins quite prominent. Responding to all stimuli with a marked preference for tongue over the head on the upstroke. Definitely above average, well into upper 25th percentile._

John gasped loudly and pushed Sarah's head away with a shaky hand that lingered on her cheek.

_Close to orgasm less than three minutes into fellatio, indicative of a long period since the last release of sexual tension. May also indicate skill of partner._

They shifted position. John braced himself against the headboard, leaning back a little as Sarah straddled him.

_Not using a condom. Doctors should know better - clearly sex makes them stupid. Check medical records of both, make sure she is using birth control._

The lovers groaned in unison.

_Several rapid, small changes in position. Unfamiliarity with one another's preferences, so an early encounter of this type._

Sarah rose and fell in a langorous rhythm, her weight supported partially by her arms and partially by John's hands on her hips. Sherlock couldn't see her face - and didn't care in any event - but he could see John's expression clearly.

_Eyes open the majority of the time, looking directly at the area of contact. Obvious positive response to visual stimuli. Aroused but still in control of faculties._

To Sherlock's surprise, John readjusted his body once more so that he could wrap one arm around Sarah's waist and place his other hand between her thighs. Sarah let out a high-pitched, pleased sound that hurt Sherlock's ears but made John smile. Smugly.

_Also enjoys pleasuring his partner, as evidenced by a speeding up of his thrusts._

John was urging Sarah onward with language that Sherlock would have expected from a sailor rather than a soldier. Her responses were boring and predictable: entreaties to God, panted orders concerning speed and pressure, and finally announcing what John surely had surmised, even through his own arousal.

Of course Sarah would manage to make her orgasm a tedious, banal experience. On the other hand, John seemed quite pleased to have drawn such tiresome sounds from his partner. He withdrew gently...

..._quite reddened and swollen..._

...and helped Sarah lie down. She groaned appreciatively at John's light touch on her breasts, then arched her back and said something appropriately pedestrian - if utterly filthy - to John that made him laugh even as he shuddered with arousal.

_Entire body tense, veins on the triceps and biceps standing out, buttocks clenched, thigh muscles twitching. Sweating profusely even though the room is probably quite cool._

They were tangled up in one another, arms and legs holding tightly as John's thrusts became fast and erratic. He, too, seemed to feel the need to announce the blatantly obvious as he drove in a final few times, almost convulsive in his release. Sherlock was annoyed that John kept his head down, forehead resting on Sarah's clavicle. He would have to wait for another rendezvous to catalogue John's expression at climax.

Ready to move on to another topic, Sherlock began to turn away from the computer screen when he noticed something he hadn't expected to encounter.

John's face.

John's face, quite close to the lens on the phone Sherlock had left on John's dresser whilst he was out on his date with Sarah.

_Red, quite contorted with anger. Eyes blinking rapidly. Lips forming words he won't want to say aloud lest he get Sarah involved in this situation._

I

Will

Fucking

Kill

You.

Sherlock blinked at the screen, almost tempted to nod even though he knew John wouldn't see it. Then John's mouth quirked in a smile and he formed a question.

Sherlock,

Did

You

Record

This?

The screen went blank as John turned off the phone.

Sherlock hit "save" and went to make himself a cup of tea.

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><p><em>End<em>


End file.
